It is well known that most of the standard specification tests are not valid when the alternative hypothesis is misspecified. This is particularly true in the error component model when one tests for either random effects or serial correlation without taking account of the presence of the other...

A new Stata command, xtsktest, is proposed to explore non-normalities in linear panel data models. The tests explore skewness and excess kurtosis allowing researchers to identify departures away from gaussianity in both error components of a standard panel regression, separately or jointly. The...